Tau V Tyranids Apoc game win

This game was played over a few days I used my Tau army and my girlfriend who took an interest last year used my Tau army. I deployed my Tau army as far back as possible using the bastion and aegis defence line as blocking terrain to hopefully slow down the tyranid horde. My opponent deployed as far up the board as possible. I got first turn and moved the fire warriors up to the defence lines. The swarms were not in range of my pulse rifles and smart missiles so began hammering in the monstrous creatures with my rail guns. I knocked a few wounds of the hierodule and tyranofex. Killing the hierodule was a number 1 priority. In her turn 1 she moved up and fired some long range weapons but the cover saves saved the fire warriors. Turn 2 I moved up my burst cannon hammerhead which excelled in this game and killed off the huge amount of gaunts and genestealers that were getting very close to my lines. I nova charged the riptide and it hammered into a tervigon knocking it down to 1 wound. There was a second line of gaunts behind the monstrous creatures which I had to kill quickly. At the start of her turn 2 her trygon and mawloc arrived close to my lines but failed to hurt my units but I had to target these creatures. On my left flank she had moved up a group of 3 carnifexes that I had neglected until they started shooting at my broadsides. In turn 3 I moved my units a bit to get line of sight on bigger threats. My crisis suits moved up and incinerated the warriors and finished them off with burst cannons. I used the 2 quad guns to hammer into the hierodule which was just behind the defence line. The riptide shredded the harpy with the nova charged burst cannon. Longstrike and the other railhead put 2 wounds on the swarmlord which was her warlord. My 3 broadside teams dealt a huge amount of damage, the high yield missiles finished off the tervigon. The heavy rail guns killed the hierodule. In her third turn she charged moved and ran everything her genestealers got into close combat with my bursthead and blew it up 5 genestealers were killed in the explosion. In my turn 4 I regrouped, pulling my fire warriors back and closer to the tanks and suits to use over watch and support fire. I left the fireblade with the quad gun furthest from the army to kill the swarmlord which he did. The carnifexes that were pushing down my left flank failed a charge and faced a huge amount of fire power from the broadsides and riptide they were finished off from a barrage from the pulse rifles and carbines. The plasma and melta suits killed the tyranofex and jumped up the board to get linebreaker. In the bottom of 4 she charged everything and got a number of gaunts and a tervigon into close combat the rest of the army was killed off in over watch and support fire. The game ended because she only had a few units left that would have been killed off in the next shooting phase. I learned that deploying close together and moving forward helps screw up deep striking units and that falling back while firing against hordes keeps them at bay and by the time they get into cc they have little chance of killing everything.