We all start somewhere... I can remember ringing my mum as I was stressing out about which ones were flowers and which were weeds. Here words which I have heard manytimes since "Weeds are plants you dont want".
As for plant choice, sit down with google and search for things like "Evergreen plants for pots" "Plants for low maintenance garden" "Early flowering plants" etc
Some key words:
Hardy - Survives frosts etc very well
Evergreen - Green year round... Trust me, you want some of these! Without, the garden will look barren in the late autumn,winter and early spring.
Perennials - Plants that persist for many growing seasons. Generally the top portion of the plant dies back each winter and regrows the following spring from the same root system
.
Annuals - Plants that perform their entire life cycle from seed to flower to seed within a single growing season. All roots, stems and leaves of the plant die annually. Only the dormant seed bridges the gap between one generation and the next.
Biennials - Plants which require two years to complete their life cycle. First season growth results in a small rosette of leaves near the soil surface. During the second season's growth stem elongation, flowering and seed formation occur followed by the entire plant's death.
https://www.themiddlesizedgarden.co.uk/the-best-plants-for-amazingly-low-maintenance-garden-pots/
https://www.finegardening.com/article/10-plants-for-year-round-containers
I agree with the idea above of having lots of pots. inexpensive medium-large plastic pots work really really well. Put some gravel at the bottom to aid drainage (you have plenty lying around
). Larger pots = less watering, small pots dry out very quickly in the heat. Easy to move around to taste, and when you move they can come with you.