How much does a joiner earn? For one project for example?

Can I work as a joiner just in the evenings and during the day work in a factory? Do you think I will be able to do two things at the same time?

Along with carpenters, joiners make and install wooden fixtures and fittings for homes and businesses. Unlike carpenters, however, joiners cut out joints that fit wood together without the use of nails and generally work in a workshop, while carpenters are often found working on-site.
Typical responsibilities for a joiner include cutting and shaping wood for floorboards, window frames, doors and skirting boards; constructing and assembling doors, staircases and fitted furniture; installing door handles and locks; fitting roof joists and timbers; and making temporary shuttering supports for building foundations or bridge supports
No formal qualifications are required for the job but it is important to be physically fit and have good practical and numerical skills. Most joiners start out as a labourer or joiner’s mate and receive training on the job, which leads to NVQ qualifications. There are also college courses in carpentry and joinery, as well as apprenticeship schemes, for which GCSEs in maths, English and design are normally required. Salaries start between £13,500 and £16,000, and could rise to £23,000 after qualification.