Here is the way you go for it.
1. Design your page completely.
2. open the page in designer, goto tools , select "generate local resource". this will create a app_localresource folder and a file aspx.resx inside that. that will be the default culture language file.
3. create as many files as you want for different culture for e.g.
for english create youraspxpage.en.resx
french : youraspxpage.fr.resx , etc..
4. edit individual files for corresponding language text.