Memory, as Liz Lochhead puts it, is a collage.

An intricate, interwoven miscellany. No matter how hard we try, "those wee imaginary snapshots of the heart and mind" tumble and fall in the mind's eye. "Memory is a creative process," adds our national poet – our Makar, to give her the title bestowed on her by the Scottish Government in 2011. "There is no difference between memory and imagination."

The 65-year-old has often mined the landscape of her childhood in the small North Lanarkshire village of Newarthill in her writing. She is turning back the clock again for this new exhibition, Competent At Peever, at Scotland Street School Museum, a Charles Rennie Mackintosh-designed building on Glasgow's south side. Lochhead, who studied at Glasgow School of Art (GSA) from 1967-1970, has spent a year here after a successful application by the Glasgow Mackintosh Group to the Iconic Artists In Iconic Places programme, run jointly by Museums Galleries Scotland and Creative Scotland.

The title of the exhibition, in which she has collaborated with Glasgow-based designers Pauline McCloy and Sha Nazir, is taken from a line in Poem For My Sister, which she wrote for her younger sister Janice's 12th birthday in 1969. The compliment-meets-put-down "She is competent at peever" describes how Lochhead liked to watch her sister play hopscotch. This poem, she says, is the one she reads most to young people, and the one which pupils want to talk about when she visits schools in her role as Makar.

It is fitting that her sister enters the frame of this exhibition from the outset, since its starting point is a wall of panels Lochhead made about their primary school in Newarthill for her second-year thesis at GSA in 1968. "When we first started thinking about this in November 2011, my first thought was, 'what am I going to put in...?'" she explains. "I knew I wanted to have poetry – my own and friends' work – in the exhibition, and I mentioned to Janice that I wished I still had the work about our old primary school. She told me she had kept it in her loft because she thought she was one of the pupils I'd drawn. By 1968, I had been away from the school for eight years and it felt like a long time ago. Now I'm revisiting it again at the age of 65, which is another step removed."

These storyboard fragments of Village and Village School, mixing words and pictures, paint a vivid portrait of the life of a small primary school in central Scotland in the years following the second world war. Lochhead's pen portraits of school characters – such as Mr Richie the headmaster, teachers Miss Lewis, Miss Robertson and Mrs Rhind – give an early indication of her talent as an exceptional writer. The yellowing typed-out texts, made by Lochhead's late mother Margaret, add to the intimate feeling.

Now, four decades on, Lochhead has used copied fragments of these panels to make new collages, on display here alongside more recent pastel drawings, interwoven with poetry "boards" on a school days theme by Lochhead and fellow poets Jackie Kay, Carol Ann Duffy, Liz Berry, Adrian Mitchell and James McGonigal. She jokes that this is her "first show since my graduation in 1970", adding "I have not got any more planned... After art school, I drew in a feartie way and of course I was working as a writer. But recently I have been doing a lot more drawing and painting, and I'm really enjoying it. And I loved sitting at my kitchen table doing these collages."

Having a residency then an exhibition in the former school building she describes as "the neglected jewel in Mackintosh's crown" has been an education for Lochhead. "It was my late husband Tom's favourite building and it has been fantastic to be around it for an extended period." This exhibition is classic Lochhead; it is direct and graphic in its imagery, be that through the written word or in her artworks. You get the impression that the two meld in her imagination. "A poem is an image," she says simply.

"I don't get a big bang out of my own work," she says. "Of course I want people to get that with my work, but I look to other artists and writers to get that feeling." Her hope for this exhibition, which also includes educational memorabilia from Glasgow Museums' monumental Resource Centre at Nitshill, such as a tawse and a copy of Schonell's The Essential Spelling List, is that it makes people get personal about their own memories.

"This is not about childhood but memories," says Lochhead. "The hope is that people will do their own work after seeing it."

Competent At Peever, Scotland Street School Museum, Glasgow (0141 287 0500) until April 7. There will be a series of events over the weekend of April 6 and 7 featuring Liz Lochhead, including a creative writing workshop from 10am-3pm on April 6. All events are free but must be booked in advance. See http://events.glasgowlife.org.uk/event/1/competent-at-peever