<form action="..." method="post">
<fieldset>
<legend>Informations personnelles</LEGEND>
Nom : <INPUT name="f_nom" type="text" tabindex="1">
<br>Prenom : <input name="f_prenom" type="text" tabindex="2">
<br>Adresse: <input name="f_adresse" type="text" tabindex="3">
</fieldset>
<fieldset>
<legend>Formation Initiale</LEGEND>
<input name="f_niveau" type="checkbox" value="bepc" tabindex="20"> BEPC
<input name="f_niveau" type="checkbox" value="bac" tabindex="21"> BAC
<input name="f_niveau" type="checkbox" value="bac2" tabindex="22"> BAC+2
<input name="f_niveau" type="checkbox" value="bac5" tabindex="23"> Ingenieur / BAC + 5
...
</fieldset>
</form>