So how can i add one box of entries? What should i do?
If I get it right, you don't want to have the "Brief description" and "Full description" fields, and want to have only one field instead. So you need to go to the module settings -> Fields of a new entry form, and disable "Entry brief description".
And what is the name of the code in viewing an entries next/prev button?
If I understand correctly what you mean, there are no system codes for this purpose.
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