I am using a default template for the main index, but my entries don't show on it (only in the recent entries link).
I guess I should add some string...
Can anybody help please?
Thank you  :)

in your main index template, where it has your MTEntries tag put lastn="7"

it should look like

Sorry but there are many MTEntries tags; I have tried in some but nothing happened...
Could you tell me the exact place please?

if you're using the default main index template, there should be only one tag that controls your entries.  the only other one is , which closes the loop that mt uses to write your entries.

you can also copy and paste your template and then i'll make the changes so you can copy and paste it in your mt.  make sure that you use the code button instead of quote when posting your template.

Thank you everybody
I've solved my problem now  :)