(Note: these rights dont apply to lodgers).
Youll have a contract usually an AST (Assured Shorthold Tenancy), which entitles you to stay in the property until the end of the contract and have full rights while youre there. Being a tenant means its easier to give notice to leave the tenancy early usually a months notice whereas landlords have to give two months notice if they want you to leave.
For as long as youre renting a property, you own the space so you can exclude your landlord (or their contractors) from coming in. If they need access for any reason, they should give you at least 24 hours notice.
But if its an emergency its probably best to drop this rule and give access right away having a water leak fixed for you is better than having to do it yourself and potentially making the issue worse
Living in rented accommodation gives you a right not to be disturbed, so your landlord cant interfere with these rights.
Youve basically just got to look after the property including decorations, furniture and appliances. Do the basics: replace light bulbs, check smoke alarms, take your rubbish out and keep the place heated properly, and keep on top of the rent and bills (obviously). If you have a garden you may be responsible for its upkeep.
If you're falling behind on payments, there's free advice from Shelter here.
For more info on your rights as a tenant, use Shelters tenancy rights checker.