If you are a starter, go for the bush variety, which are easier than cordon. But saying that none of it is rocket science.
One of the best cordons is Sakura F1 - a red Cherry which has superseded Sungold.
A bush tomato that can be grown in pots is Tumble - another small tomato.
But honestly as far as tomatoes are concerned - the world is your oyster.
If you have no heat then don’t sow until mid-end March and don’t stint on keeping them warm. Think South America heat.
Saying all that the easiest plan is to buy plants when the become available - say in May, but your choice will be very limited.
You can get all the information you need on line.
We have access to heated propagator, heat pads, greenhouse etc. so DH will be starting sowing his next week, which generally means that you can be picking tomatoes from June through to November.