HMRC issue step by step guide to CJRS claims and an online calculator

HMRC have issued a step by step guide to making the Coronavirus Job Retention Scheme claims as well as an online calculator. The calculator has limitations but can be a helpful tool

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/880099/Coronavirus_Job_Retention_Scheme_step_by_step_guide_for_employers.pdf

https://www.tax.service.gov.uk/job-retention-scheme-calculator/