Hi i have just set up my first tank , i started off by adding a few fish at a time , first 6 neons , the following week i bought 6 guppies , the third week (this week ) we have swordtails and also a Siamese fighter .I think the main thing to remember is only to add a small number of fish each week.There are plenty of experts here who i am sure help you out .There are several posting on the same topic and from what i have read just take you time when adding new fish ,keep up with water changes and enjoy your tank