1. Basic Computer Literacy
ECF Arbiter Seminar - Materials by CAA

2. Tasks on a Computer
Arbiters nowadays are expected to be able to use computers to do some of the following:
Produce signs during play
Produce Prizelists
Enter results
Enter Player details
Do Pairings
Calculate title norms in FIDE rated events
Report results by

3. Computer Software Programming Software Grading/Rating Software
Word Processing
Spreadsheet
(Databases)

4. Pairing Software
There is a variety of this software available. It is recommended that software approved by FIDE is used.
The most commonly used are SwissMaster and SwissManager. The former is more intuitive but the latter can upload to Chess-Results.
Whichever is chosen it must be used in trial runs before a tournament.
Most programs will allow you to test them out before buying, restricting the number of rounds or players.

5. Testing Pairing Software
Things to do in a trial run.
Enter players
Do pairings
Enter results
Produce print-outs of pairings and chart
Alter pairings/repair players
Know how to deal with defaults