Without Studio (see "change limit without studio) :

1. Go to the list view you want to modify

2. Click on "the scarab" in Debug mode and then "edit action"

3. Change the field called "limit"

4. Add the text in bold at the end of the first line of code <kanban default_group_by="stage_id" class="o_kanban_small_column o_kanban_helpdesk_ticket" limit="number of records">

You are not allowed to change the limit on some model by this way (by example; SO lines in Sales Order).

For those model, you have to use Studio (see "change limit with studio") :

1. Go to the list view you want to modify

2. Open Studio in Debug mode

3. Do a small change on the view to create automatically an inherit view (by example; flagg in "Required") 

4. Click on the "</>XML" icon

5. Select the inherit view called "Odoo Studio: customization" and add:

  <xpath expr="//tree" position="attributes">

    <attribute name="limit">56</attribute>

  </xpath>