Getting a mini greenhouse -where to start?

[lightlypoached]

Hello sage gardeners. I've got a titchy garden and have invested in a mini greenhouse. Idea being I can grow 1 early tomato (next year now), chilli plants, lettuce and somewhere to start seedlings.
It won't arrive until June. I've been gardening for years but never had the luxury of a greenhouse before.

Please can you share your ideas of what I could grow this year, and ideas of which plants might work in a small space (it's 1.5m high and 40cm deep)?

Any guidance appreciated

I start off my runner beans in my mini greenhouse - it's one of those metal frames shelves with a poly cover that zips at the front. Taller growing plants on the top, anything that grows smaller on the next 2 shelves down. Currently got rocket growing in the bottom and I started off beetroot, tomatoes and some wildflowers on the next shelf up.