Greenhouse position

It can't go up till the water subsides on the plot a bit, but I am planning chillies tomatoes melons sweet potatoes and aubergines in my head....

Just bought some watermelon seed from Lidl thinking of my new second hand greenhouse - back of seed pack tells you nuffink at all really - I feel some Google research is in order. I take it you already have melon seeds?

I've got the same seed from Lidl but 30 in the pack for 20p when you buy 5 packs    Thanks for the link and little of no guidance on the back of the pack