A question about Taxes and what you've done or are doing?

Hey all,

I live in the UK and I have sort of ignored Crypto for the past 4 years or so and I got into it back in 2017. I was a noob and I bought and sold bought and sold and didn't really think about it. I made money in crypto coins and then it all crashed and I ended up with less than I put in. So I just kept the money in there in hopes that it would rise again.

In 2020 I kept an eye on things and as it started going back up I took some of my money back (still below what I put in) and I kept the rest in there.

I started to look at the potential Tax issues and I don't really understand it so I took a download of all my trades from sites and then I sold everything and transferred the money back to my bank account. A few days later I bought back some of the coins I wanted to start over fresh and I've just left it in there since.

So my question is what do I do about paying Tax and declaring things? I still have less than I invested and I haven't invested any more as I'm mainly concerned that if I do make any money I'll have to pay a load of money anyway and probably won't end up with that much. So I've just kind of left my money in there for now.