@keyboardkate yes, although if you had a cs pension pre-2016 it might be slightly lower. This will also depend on your age but you will be entitled to some, if not a full state pension
Alpha is roughly worked out as follows:
Year 1: salary is £20,000pa. At the end of the year your pension will be £464 (2.32% of £20,000)
Year 2: salary is £20,000. The £464 from year 1 will be increased by inflation and then the £464 earned in year 2 will be added. Say inflation was 1%. So your pension at the end of year 2 will be £464 increased by 1% plus the £464 earned in year 2 = £932
Year 3: salary increased to £25,000. So pension earned in year 3 is £580. If inflation was 1% then the £932 would be increased to £941 then the £580 would be added on to make £1582.
If you left after year 3 then when you reach retirement the civil service pension will pay you £1582 a year (although this amount is subject to inflation so could be higher by the time you get to retirement age)
If you carried on working then your pension will carry on being built up as above until you leave or retire.
So, it's not easy to work out your pension in retirement as you do not know what inflation is, what your salary will be or how long you will be a member of the scheme for.
With regards to pension contributions, you will pay whatever the scheme requires you to. Your employer will contribute however much they need to to make sure the scheme can pay what they have promised to pay you.
With traditional final salary schemes the calculation is much simpler. It is your salary when you leave the scheme x how long you were in the scheme which is then divided by a factor (generally 60 or 80). So, final salary benefits tend to be more favourable (and more expensive to run) than career average as a persons final salary tends to be higher at the end of service.