Hargreaves lansdown has a great app and site, plenty of information, trades are £12 though, plus 1/2% stamp duty uk stocks (1% ireland)
if you setup a monthly investment saver, they take a direct debit off you around the 3rd/4th of the month and then purchase the shares/stock funds on the 10th of the month, fees are £1.50 per stock.
this is probably the best way to drip feed funds into an account, although you have no control over the price they buy at, its done on a fill/kill at best order on the date, i’m currently buying a few companies shares investing £50 a month, which will be £600 of investment per stock after a year..
as others say diversify, i’m a bit heavy on uk banks, so on good days its good, bad days its bad..
before last thursday i was up 15% in 2 weeks, then down 8% in 2 days..
far more interesting than 0.000001% interest at the bank..
remember high risk = high reward (or loss)
as others say stay away form CFDs as that will escalate risk