There are many places where you can find useful information for building or renovation projects and the associated electrical work, here are just a few which you may find helpful.
All electrical work - no matter how small the project - must be undertaken in accordance with the relevant standards and regulations, and the best way to guarantee this is to use appropriately qualified staff. These are usually known as 'registered competent persons'.
If you are planning a major building project eg, a new house build, then you will need to obtain both Planning Permission and Building Regulations Approval. You will probably also want to consider a Building Warranty (any mortgage providers will ask for this) and a site insurance policy. Smaller projects will probably still need Building Regulations approval and may need some or all of the others as well, so you need to do your research or ask an expert for help.