Great that you have a savings habit and a useful lump sum. The secret now is to save regularly each month but to do this you need to be at the point where you have a regular income. So finding jobs which you enjoy, which pay reasonably and where you can progress is the foundation. The 50 / 15 / 5 gives an indication of saving targets. 50% is the indication for how much to spend on essentials like bills and food. 15% long term saving like house purchase deposit and pension and 5% for an emergency fund. This still leaves 30% for fun things which is very important.
The other secret is to find some investment which make a reasonable return at sensible risk level eg company pension schemes, company share schemes, share ISAs etc. Investing doesn’t have to take time if you use products others have developed although you do have to pay the fees. Get some free advice on line and from your bank.
Interest rates for savings accounts are woefully low currently, it’s a struggle to find 1%. If the interest rate you receive is below inflation saving are depressingly being depleted rather than growing although for relatively small amounts of money and periods of time this is neither here nor there.