Gains and Losses in Selling of Stocks

HMRC Admin, I had sold several stocks in the tax year. There were gains (G) and losses (L) but the overall (G minus L) was a loss. I have the following queries: (1) Should I fill in the gains (G) and losses (L) separately? OR fill in the overall figure (G minus L) in the tax year? (2) Could I ONLY fill in the amount of gains (G) in the current tax year, and then carry forward the loss (L) to the next tax year? Thank you.

Hi,
Please refer to Capital Gains Tax summary notes
Thank you.