In wordpres website we can make custom menu very easy that I am sharing my views here. First you have to go wtih Admin Dashboard then click on post you will get these link like all posts >>Add new>>Categories>>tags.
Step 1):Just one click on categories link it will go to create a category form. See the following screenshot for better understanding.
Step 2):After clicked on category Add new category form will come then enter category name here.
Step 3):After adding all categories what all the menu Items you want to show on website. see here some example categories in our website.
Step 4):After adding all categories you have to go to appearance and click on menus link.
Step 5):After clicked on menus link then you will get below screen which tells us create a custom menu and add to all categories to that menu and just save it.
Step 5): Finally you have to custom menu for your theme. so that here click on theme customization then select the custom menu from navigation drop down.
I hope you have got my point. Enjoy keep on visit my blog, it will help you a bit.