Begin creating a new filter by clicking the 
icon, you'll then be prompted to give the filter a name.
Next you can then begin configuring your filter by working your way down through the filter options ticking those you want to use in your filter.
Start Time
Here you can configure the filter to only find markets due to start in a specific time or within a specific time window.
In the example below when the filter is used it will only find and display markets that have not yet past there start time, but are due to start within the next 5hrs.
Event & Market Type
This option lets you specify the type of 'Event/s' you want the filter to include.
When you arrive at the 'Filter markets by Market Type’ option a little further down only the market types relating to the Event/s you have selected will be displayed for you to choose from.
e.g. In the example below for the 'Event Type' I've chosen to filter for 'Greyhound Racing', when I reach 'Market Type' area only Greyhound related markets types are being displayed for me to chose from - making it much easier to find the market types required than if all types were displayed.
If you don't select any events when you reach the markets type every market type for every sport will be listed for you to select from - and there's a lot!
Country Filter
You can use this filter to restrict which countries' markets are included by the filter. For example you may want to find all horse racing 'win' markets but only from 'UK' and 'IRE'
Filter by Text
Filtering markets by text behaves just like it would in the regular market search area. You can insert the words 'AND', 'OR', NOT, into your search string to build more complex search criteria. e.g. a typical search string could look like 'English AND Premier AND Match Odds'
If creating a horse racing filter to find only flat races you would use something like 'NOT Chs AND NOT Hrd'
So why would you not just search for 'flat' in here?
It's due to how Betfair name their markets. Any search term you use has to somehow match with Betfairs naming of the markets, if you navigate your way through the main market tree on the 'Select' tab when you get to racing markets you'll see the word 'flat' does not appear next to any races - including those races that are run on the flat.
However they do use the words 'Chs' and 'Hrd' which are abbreviations for Chase and Hurdle next to national hunt jumps races.
Therefore you can achieve your objective of filtering for flat races by eliminating jumps races using the search string 'NOT Chs AND NOT Hrd' in the text area.
It sounds hard at first but once your accustomed to how Betfair name there markets by inserting a combination of 'AND', 'OR', NOT, into your text search you can find or eliminate your required markets.
Traded Volume
This option lets you enter a minimum traded volume, its possible to filter for this at 'Market Level' i.e. if your searching for Correct Score markets of a football fixture and enter £5000 then it will only find Correct Score markets with more than £5000
Alternatively if you were searching for the same market but used 'Event Level' then as long as ANY market from that football fixture has a greater than £5000 matched (this could be the Match Odds market) then the Correct Score market from the fixture would be found for you.
Show Only Markets Going In-Play
This does what it says on the tin so when used will only find markets that Betfair allow in-play betting on. This is handy on both Football and Horse Racing markets where markets from some countries and/or leagues may not be put in-play.
Show Only Markets In/Not In-Play
This filter checks the current in-play status of a market. This is especially useful if your an in-play trader and are looking for markets like Football or Tennis which have already started, or perhaps your a pre-off football trader who only wants to see markets which have not yet kicked off.
Using those filter options you should be able to home in on just the markets your want for your trading session. Remember you can create as many filters as you wish, then with a click of your mouse, flick between them to find exactly the markets you want.
In the image below I have created 4 different filters for 3 different sports showing how easy it is to find and display markets once you have created your filter.
