Making heros is very similar to making items - if you know that, you'll be able to do this.
Click on the Heros Tab in the Main Map Editor window to get this:
The first button is for Opening a Library (open folder with face), so you can load a hero from a pre-existing library.
Next comes Edit Hero (the pencil), this allows you to edit a hero which you have previously created either in a library of your own or right there on the map only - you cannot edit heros from the System Library.
Add Hero (with the plus sign) is for you to create a hero on this map only. (Libraries are discussed in the other section)
Delete Hero (with the red cross) from this list, if you don't want him/her around on the map ever. If the hero exists in a library, you can always reload him/her again if you should change your mind.
The ABC and the 123 are for sorting of heros by name or by race respectively.
To Create A Hero: Click on the Add Hero.
Name your hero - 15 letters only! And don't the great ones get Titles? Eric (name) the Brave (title)
Fix the race and gender.
Different races have different fixed starting statistics and abilities but genders do not have an effect. If you don't like the face portrait, click on Change at the bottom of the face graphic. (Yep, just like the one in the item creation). Usually, the face befits the gender. ;-) Unfortunately you cannot put your own portrait in this one.
Note that when you increase the levels, you get more skill points which means you get more points to the Statistics and more Available Abilities to add to Selected abilities. Skill point assignments to statistics and available abilities work the same way as customised heros during an active game. Each ability and statistic will cost skill points (sp). e.g. to increase defense by 1 will cost sp=5.
Notice that there is also an Items Tab in this Hero Properties window. Click on that and you will also get the Items Floater. As you can see you can also preassign items to your newly created hero. Body Items is what the hero wears and Inventory is what the hero carries ("Use" items such as bows and wands) Assign items by clicking on them and then click on Add. (This tab does not exist when creating a hero within a library.)
Tip: This is useful. Heros can carry items that enhance their statistics, so you don't always have to create a hero and assign any points to the statistics, give him an item - a sword or a cloak that enhances some of his statistics by 1 or 2 points. This also adds character.