To become formally involved you need to actively attend your branch meetings. To find out what branch you are in check your membership card.
On your branch you can become a Branch Equality Officer or Strand (Women, LGBT, Race, Disability, Youth) Equality Officer. Once you are officially in one of these roles you can attend your Local Equality Forum, these are localised forums that meet every other month.
Once at these forums, you can be elected to attend the Regional Equality Forum.