hi i'm doing a side to side stemplot and i have a question.here are a few numbers of the data:

186
181
176
149
184
190
158
139
175
148
152

is is best if i round the data like 190, 180, 180, 150, ... and then do the stemplot or just directly do it.

this is the i might do it if i round the figures?
then as the stems, what would i put because this is a three digit number? do i put 14, 15, 16, 17, 18, and so on? Do i have to start the stems with a 1 or just start numbering according to the data?

No, I don't think you should round the data.
The stems should probably be the numbers 13,14,15,...,19
Line them up like this with the leafs to the right
S L
13 |9
14 |8,9
15 |2,8
.
.
.
You can finish it.
Starting the stems with 1 would accomplish nothing here. You can order the data to begin with, the order shouldn't matter when doing stats.