We are making a transfer at Alvesta Train Station. We have 10 minutes for the transfer. Every combination of trains between Kalmar and Stockholm has this same 10 minutes transfer at Alvesta. Will we have trouble finding and getting to the next train on time?
10 minutes is not a short transfer. This is just an efficient railway trying not to waste the time of its customers. (In Switzerland you will even get much shorter transfers).
Do not worry. Just listen to announcements on the train, pay attention to screens. Look at what other travellers do. Most probably you will end up wishing that the transfer was less than 10 minutes. Alvesta is a small station, you will not need more than 1-2 minutes to get to the platform of your train to Stockholm.
And if a delay does make you miss the connection you just take the next train.
You can look at arrivals and departures at Alvesta here:
https://loktid.se/en/station/alvesta/departures
So trains from Kalmar usually arrive at 3b, and trains to Stockholm leave from 2. So your transfer will involve taking one set of stairs down, walking 10 m, then another set up. Should not take you more than 2 minutes. So plenty of time to postion yourself so you are at the right spot for the car you have reserved seats in.