installing a towel radiator can be tricky but this guide shows one way of installing a towel radiator. Before fitting the radiator you need to drain down the system which can be seen in this video https://www.youtube.com/watch?v=wn008wmHr_A
When joining the chrome pipe it is best to use a compression fitting as these are compatible with chrome pipe. Other fittings can be used but you must remove the chrome plating first, which can be difficult!
For more central heating advice please see here https://www.ultimatehandyman.co.uk/central-heating.php