You can run an interactive job like this:
$ srun --nodes=1 --ntasks-per-node=1 --time=01:00:00 --pty bash -i
Here we ask for a single core on one interactive node for one hour with the default amount of memory. The command prompt will appear as soon as the job starts.
This is how it looks once the interactive job starts:
srun: job 12345 queued and waiting for resources srun: job 12345 has been allocated resources
Exit the bash shell to end the job. If you exceed the time or memory limits the job will also abort.
Interactive jobs have the same policies as normal batch jobs, there are no extra restrictions. You should be aware that you might be sharing the node with other users, so play nice.