MK111 timer - extend pulse time

Kits Timers and Clocks
1

I need to extend the pulse time to something like 10 seconds. Would increasing value of R1 do this for me. I know you cannot help with values of components , but am I on the right track.

2

Yes, R1 and/or RV2 can do the job.

for more info, see NE555 datasheet:

fairchildsemi.com/ds/LM/LM555.pdf