Ann: Sayona Advances Exploration Activity in Canada & Australia, page-19

Either sell the rights (SYARD) which you can do in the normal way on Commsec trading platform, or convert them to ordinary shares by paying the 3.2c per rights unit.
If the latter (ie converting), you need to pay using the BPAY details on the "EntitlementAcceptances" form you may or may not have received,dependent on your notification delivery preference - (maybe mailed hard copy, or emailed to you as a pdf document?).
If you don't have the form, it will be sitting on your Computershare portal. If you don't have a Computershare account, I guess either create one, or ring them (or SYA) to get a copy of your personalised form.

Hope this makes sense & helps.