Friends, the easiest manner to build an encounter is to simply pick an enemy from the Monster Manual in front of you with a CR around almost the same as the level of PCs in your party. This could be one higher if you want them to give you a tough fight or more competitive by nature.
In the 5th Edition, mark that outnumbering your opponent can be quite an advantage. Be cautious before putting yourself up against a deadly encounter, especially against lots of enemies.
1. First, you need to mandatorily fill in the number of characters in your party and their level. If characters in your party are at different levels altogether, then add multiple rows and include each group of the characters with the same level in their own row.
2. Next, hit calculate to see the encounter XP thresholds for the given party.
3. Finally, fill in the number of monsters and the amount of XP that each one gives in a similar manner. Now, once again hit calculate to see details about the encounter and to get a difficulty rating for the encounter given your party.
Alternatively, you may check the “Use Challenge Rating (CR)” box, fill in the number of monsters and the CR for each monster rather than its XP level.