how to get to spacial rift?

Hmm, have you already went to talk to lapras again? Try that. Palkia comes to you one night and kidnaps you to spacial rift where you get to battle him. You then realize that darkrai is the fake cresselia and then, you go meet the real cresselia at sharpedo bluff so she can take you to dark crater to battle darkrai but be careful because he has some Pokemon from the dungeon such as rhyperior, aggron, magmortar,mismagius,and arbok. Then you get to the part which I am currently at.

It's a long explanation, so brace yourself!
You must do a few optional missions (or roam in dungeons), then eventually when you stop by the guild, Team Charm will be there, talk to them, they tell you about Aegis Cave. After that go there, the first cave you must find the I, C, and E unown stones and fight Regice, then the R, O, C, K stones and fight Regirock, then deal with the S, T, E, E, L stones and fight Registeel. After that you must go through the Aegis Pit. In Regigigas' Chamber, you'll team up with Team Charm. Be careful! There'll also be four Bronzongs and four Hitmonlees (your best bet is to bring your Dialga with you, It's roar of Time will do the trick!) After taking care of every one of them, that objective will be complete. (don't worry about the newly unlocked dungeon.)
Next, after a few optional missions, Azurill will be envleloped in a deep nightmare. You must head to Mt. Travail (Careful, you can only bring You and your partner). After speaking to Drowzee, You will be asked to go into Azurill's Nightmare, after you do so and speak to Lapras after a few cut scenes, Palkia will warp you to the Spacial Rift. You must Defeat Palkia at the end of the dungeon. After meeting the real Cresselia, You will finally go to the Dark Crater, at the pit you will face Darkrai, along with him is Rhyperior, Arbok, Magcargo, Magmortar, Aggron, and Mismagius (don't worry, Cresselia will be with you). You MUST defeat all of them and Darkrai to win. The difficulty is based on how your team's built.

Help my team is mudkip and pikachu

Moves
Mudkip. Pikachu
Tackle. Thunderbolt
Water gun. Dischrge
Ice beam. Shock wave
Hydro pump. Thunder

My levals are mudkip lv55 &pikachu lv 54

You get to fight palkia after beating azurill's nightmare level. You get darkrai after you beat palkia

And ill continue from the long story thing after defeat darkrai cresselia will be at the edgde of sharpedo bluff talk to her and she will ask if she could join you say yesdo 3 missions chatot will come running sayind manapys back then go to beach keep talking then it will ask can join say yes you do 3 more missions and it will come and say about marine resort win that and then go back to spacial rift defeat palkia again he will join then run to luminous spring and be at a high enough level to evolve your leaders now I will explain about team raider and dugtrio at the beach staying there all day all night just get to master ank get all legendary Pokemon but you don't have to get the ones with secret slab or mystery part and win all dungeon even wonder mail ones go to pmd2 wonder mail generator and also zereo isle then go to the guild bottom floor talk to diglet go to beach and talk to dugtrio and then team raider then you have to battle team raider then when won I don't know whats next I think your parthner goes to the guild doing somthing you find out for yourself...