The main tenant liabilities are:-

–  Pay your rent on time.
If you believe that you are going to have problems paying all the rent, it is critical you make contact with the landlord to discuss it with them.
It would be unusual if you are unable to pay the whole rent, so discuss how much you can pay that month, and try to come to some sort of agreement how you pay back any arrears.
You want to try to avoid the possibility of getting evicted because of excessive rent arrears, and especially the danger of a County Court Judgement (CCJ).
If you want independent advice, go to Citizens Advice – see their page on this

–  Look after the property, and ensure you report any problems to the landlord, at the appropriate time.
Again, Citizens Advice have a page on this.

–  Allow access for the landlord, and their workmen to rectify any problems, and to renew any legally required checks, e.g. the annual gas safety inspection.

–  Follow the terms of the tenancy, especially one that does allow you to allow other people to live in the property.
If you are a family unit, or two unrelated people living together, and you allow an unrelated person to live you, you will have a House of Multiple Occupation (HMO).
Depending on the circumstances, an HMO might have to be licensed. If the landlord does not licence because they are unaware of the extra tenants, you might have problems.

–  Request permission if you intend to run a business from the property. The landlord insurance might preclude this, and this might invalidate the insurance.

The main thing is, keep communication with your landlord.