Publishing slots, one at a time or by the term
The publisher asks only for a start and a repeat count — which is also the whole of the weekly-pattern mechanism.
Open the listing for editing. Below the fields is a Bookable slots section: everything already published, and this form.

Start (date & time) is when the slot begins. The end is worked out from the listing's own duration — you set that once on the listing rather than per slot, which is why this form asks only for a start.
Repeat for N weeks is what makes this bearable. Leave it at 1 for a single
slot. Set it to 8 and you publish that same weekday and time for the next eight
weeks in one go — the normal way to open a term's worth of a regular weekly
commitment.
Publish is immediate. The slot is visible to buyers as soon as it is saved; there is no separate "make available" step.
Building a weekly pattern
There is no separate recurring-schedule screen — the repeat count is the whole mechanism. To offer Tuesdays at 18:00 and Thursdays at 20:00 for two months, publish twice: once from the first Tuesday with a repeat of 8, once from the first Thursday with a repeat of 8.
That is deliberately simple, and it has a consequence worth knowing: each published slot is an independent thing from then on. Changing your mind about Thursdays does not "edit the pattern" — it means cancelling the Thursday slots you no longer want.