You should have been given a special link to use for editing your attendance. The link will end with something like ...?t=VDcHOaWWq0XHUwXDD6wJZwzKTqbciiKwoFrToTZ8, that is, with a string of 40 seemingly random characters. You need to use this link every time you want to edit your attendance, so it would be a good idea to bookmark it.
Use the drop-down menus to indicate which rehearsals you will be attending. Once you have finished making your changes, you need to click the Save changes button at either the top or bottom of the register.
When you use your special link, for your convenience, your section and part will have been moved to the top of the register. All the other instruments appear in a conventional order.
Also note that you may not be required for all rehearsals. You will not be able to incicate your attendace at those rehearsals. Instead, of a dropdown menu you will see a '-'.
As a shortcut, you can use the arrow keys on your keyboard to move around the register. (This does not work in Firefox.)
As well as the standard view of the register as a big table, you can also go to a that just shows information about your attendance. This is probalby easier to use on a mobile phone, or other device with a small screen. You may also find it an easier way to update your own attendance on a desktop computer too.
Underneath the register there is a link Download iCal file (to add the rehearsals into Outlook, etc.). If you click that link, then a file will download. You can import that file into Oulook, Google calendar, iCal, and many other types of calendar software. This will automatically set up information about all the rehearsals in your diary.
Note, that to make this work with Outlook, it seems you must first save the orchestra.ics file on your desktop, then go to File, Import and export ... in Outlook to Import it as an .vcs file. If you just open the file with Outlook, then it will only import the first rehearsal. Any other calendar program just seems to work without complications.
If, later, the times of any rehearsals are changed, you can click the link again, and the rehearsal information that is already in your diary should be updated automatically.
There is a link at the bottom for getting the register in a format suitable for printing. This is most useful for organisers, but it is available for everyone.
Normally, the register only shows the events that are still in the future. If you want to see the information about past rehearsals, then there is a link underneath the register to do that.
There may be several different series of rehearsals (for example, rehearsals leading up to the spring concert, and rehearsals leading up to the summer concert). If that is the case, there will be a row of link underneath the register to let you switch between them.
For example, if you forget your special link, or cannot use the system, then look at the small text at the bottom of the screen. There may be a Get help link there, if the administrator has set one up.