I have picked up your correction and I am working on that.

Busy day

I am in a KOTESOL conference today.
The presentations  that I Joined attended were great!!!

A busy but happy day!

I think that the verb "to attend" is better here than the verb "to join"

and we want the past tense. Both verbs form the past tense by adding -ed at the end.

join ---> past ----> joined

attend --> past ---> attended.

There are a lot of English language verbs that are not regular, for example

see ---> past --> saw  (not seeed which would be very strange)

Busy day

I am in KOTESOL conference today.
The presentations i Joined were great!!!

busy but happy day!