Let’s start with the alphabet. It’s what I first learnt. Just like with writing, learning the alphabet made it easier down the road when learning words. Letters make the words right. Some word signs are linked to the individual letter signs too.
BSL uses the two-handed fingerspelling. Some other sign languages may use only the one hand. The alphabet is used when the signs are not known for words or there hasn’t been a sign assigned. Like names for example.
TIP: The fingers of the non-dominant hand, so my left, represent the vowels; A E I O U. When these signs are used, I will point my dominant hand, my right to the finger the letter represents.